Due seminari presso il DISSTE

AISAM é lieta di condividere due seminari che si svolgeranno il 14 Giugno 2023, a partire dalle ore 14:30, presso il Dipartimento per lo Sviluppo Sostenibile e la Transizione Ecologica (DISSTE), Piazza Sant’Eusebio 5, Verceli, in aula D11:

1. Stefano Alessandrini (NCAR, USA), visiting presso il DISSTE, terrà un seminario dal titolo “The analog ensemble system and its applications”
2. Daniela Tordella (POLITO), Associate Professor DISAT, terrà un seminario dal titolo “Lagrangian measurements in the atmospheric boundary layer and inside warm clouds by means of clusters of mini radio probes”

Maggiori dettagli nei corrispettivi abstract.

1. Abstract. “The analog ensemble system and its applications”: In the last few years, the analog ensemble (AnEn) technique has been extensively tested for a wide range of applications ranging from renewable energy to meteorological reanalysis. It provides accurate deterministic estimates and reliable uncertainty quantification by generating an ensemble from a deterministic prediction and a historical data set including observations of the quantity to be predicted and predictions from the same system. The AnEn has been applied to generate both short-term predictions and multi-year resource assessments of wind and solar power, rainfall reanalysis dataset and gridded meteorological predictions, among others. Examples of these applications will be shown with an analysis of both deterministic and probabilistic skills. For the former, traditional metrics as root-mean-square-error, bias, correlation, and mean absolute error will be examined, whereas important attributes of probabilistic predictions as statistical consistency, reliability, sharpness, resolution, and spread-skill relationship will be assessed for AnEn and the methods to which it is compared. Some of the recurring features of AnEn across the different applications are:
   • Reduction of systematic and random errors and an increase of the correlation between the predictions and the observations with respect to the deterministic prediction used to generate AnEn;
   • The possibility of using a higher resolution model (since only one deterministic forecast is needed to generate an ensemble);
   • No need for initial condition and model perturbation strategies to generate an ensemble;
   • Intrinsically reliable estimates (i.e., no postprocessing required);
   • Ability to capture the atmospheric flow-dependent error characteristics;
   • Superior skill in predicting rare events when compared to state-of-the-science post-processing methods and traditional ensemble methods based on a set of numerical weather predictions.
2. Abstract. “Lagrangian measurements in the atmospheric boundary layer and inside warm clouds by means of clusters of mini radio probes“: Clouds determine precipitation and constitute the main compo- nent of the hydrological cycle. They can be very beautiful, but also emphemeral in the eyes of people, artists, but also of scien- tists, thereby creating a fascina- ting enigma. The scientific study of clouds be- gan with Luke Howard’s classification in 1803. Throughout the 19th century, the boundary between the arts and sciences, particularly with regard to natural sciences, including meteorology, was much less rigid than it is today. For instance, the great German poet Goethe took particular interest in the scientific classification of clouds. The most original sea-and-sky scape painter of the 19th century, JWM Turner, annotated his copy of Goethe’s ‘Theory of Colors’, and referred to it directly in the title of one of his paintings (Light and color (Goethe’s theory)—The Morning After the Deluge—Moses writing the book of Genesis (The Tate Gallery, London)). And one the finest of all cloud painters, John Constable, was also well aware of the work of Luke Howard, and performed detailed cloud studies in the 1820s over Hampstead Heath. It is now understood that, paradoxically, the global dynamics of the atmosphere and climate are very much dependent upon the microscale-level processes of clouds. In fact, in addition to convective heating due to the latent heat release associated with the condensation of water vapor, clouds control, to a large extent, the solar and thermal radiation balances of the atmosphere. The present seminar course mainly focuses on a few of the fundamental aspects concerning clouds:
   • The condensation of water vapor and the subsequent precipitation within clouds through microphysical processes that take place at cloud particle size scales, ranging from several micrometers to a few centimeters.
   • The development of improved observational techniques to study microphysical processes and bulk cloud properties and to measure the physical and optical properties of atmospheric aerosols.